The error code 0x0000059E translates to ERROR_INVALID_MSGBOX_STYLE. This error occurs in Windows programs when you use the MessageBox function to display a message box with an invalid style flag.

Understanding Message Boxes:

• Message boxes are modal dialogs used to display messages, icons, and buttons to the user.
• Different style flags can be used with MessageBox to customize the appearance and behavior of the message box (e.g., buttons, icons, modal vs. non-modal).

Causes of ERROR_INVALID_MSGBOX_STYLE:

• Incorrect Style Flag: The most common cause is providing an invalid flag or a combination of incompatible flags in the uType parameter of the MessageBox function.

• Missing Required Flags: In some cases, omitting essential flags for the desired message box type (e.g., button types) can also trigger this error.

• Code Errors: Mistakes in how you’re constructing the style flags or calling MessageBox can lead to this error.

Troubleshooting Steps:

1. Verify Style Flags: Double-check the documentation for MessageBox to ensure you’re using valid and compatible style flags for the type of message box you want to create. Common flags include MB_OK, MB_YESNO, MB_ICONINFORMATION, etc.

2. Review Flag Combinations: Some flags might have restrictions on how they can be combined. For example, you can’t use MB_OKCANCEL with MB_YESNO simultaneously.

3. Debug Function Call: Use debugging tools to inspect the value you’re passing for the uType parameter in the MessageBox call. This can help identify typos or invalid flag combinations.

4. Consult Documentation: Refer to the documentation for MessageBox to understand the available style flags, their meanings, and any usage guidelines or compatibility information.

5. Use Flag Constants: Consider using constants or well-defined variables to store the style flags for different message box types. This improves code readability and reduces the risk of typos or incorrect combinations.

Additional Tips:

• Explore using higher-level UI libraries or frameworks (if available) that might provide more user-friendly abstractions for creating message boxes, potentially simplifying style flag management.

By following these steps and understanding the reasons behind the ERROR_INVALID_MSGBOX_STYLE error, you should be able to identify the issue with your style flags and fix your code to create message boxes with valid styles using the MessageBox function.